Prepaid long-distance telephone calling cards are very popular, but they have drawbacks. The prepaid card will typically have a face value for the total value of calls that may be dialed. In addition, the card will typically have an expiration date that is determined based upon the date the card is first used, for example based upon a standard usage interval such as a three-month period. The would-be purchaser of a prepaid calling card faces the problem of trying to guess how many calls he or she will make during the usage interval. If the would-be purchaser selects a calling card with a high value, there is the risk that the usage interval will have ended before the entire value gets used. This loses money from the point of view of the purchaser. On the other hand, if the would-be purchaser selects a calling card with a low value, the purchaser may use up the value long before the usage interval has expired, thus facing the prospect of having to incur the time and inconvenience of making another purchase of a calling card right away.
A user of a purchased calling card may wish to give a card to someone else after it has been partially used. The recipient may prefer, however, to know how much stored value remains, simply by looking at the card. Prior-art cards do not offer such a capability.
These problems have existed for a very long time and have not, until now, been successfully addressed. It is clear that there is a great need for an approach that permits a user to purchase a large-value calling card without having to worry about losing some of the value of the card due to expiration of a usage interval.
One approach to these problems is to make and sell small-value calling cards. Instead of buying, say, a ten-dollar card, a purchaser could purchase five two-dollar cards. This is a nuisance for the seller, who must stock and count and inventory perhaps five times as many cards if this approach is followed. It is also a nuisance for the buyer who must carry around five cards. Such a buyer may be annoyed to have some unexpired value associated with a first card (out of a group of, say, five cards) that cannot be used in conjunction with a second card.